Using a Rainfall Simulator to Define the Effect of Soil Conservation Techniques on Soil Loss and Water Retention

In the Czech Republic, the Universal Soil Loss Equation provides the basis for defining the soil protection strategy. Field rainfall simulators were used to define the actual cover-management factor values of the most extensively seeded crops in the Czech Republic. The second purpose was to assess rainfall-runoff ratio for different crops and management to contribute to the debate of water retention effectiveness during approaching climate change. The methodology focused on multi-seasonal measurements to cover the most important phenological phases. The rainfall intensity was 60 mm center dot h(-1) for 30 min and a plot size of 16 m(2). More than 380 rainfall simulation experiments provided data. Soil conservation techniques proved to have a significant effect on runoff reduction. Conventionally seeded maize can reduce the runoff ratio to around 50%. However, cover crops combined with reduced tillage or direct seeding can reduce the runoff ratio to 10-20% for 'dry' conditions and to 12-40% for 'saturated' conditions. Conventionally seeded maize on average loses 4.3 Mg center dot ha(-1) per 30 min experiment. However, reduced tillage and direct seeding reduce soil loss to 0.6 and 0.16 Mg center dot ha(-1), respectively. A comparison with the original USDA values for maize showed that it is desirable to redefine the crop cover factor.